.btn {
    margin: 5px;
    background-color: rgb(8, 92, 238);
    color: #fff;
    transition: opacity 0.5s ease;
  }
  
  .btn:hover {
    opacity: 0.6;
    transition: opacity 0.5s ease;
  }
  
  .btn.active {
    background-color: rgb(3, 150, 0);
  }